Baron Omatsuri is the main antagonist of the sixth One Piece movie.

He claims to be the owner and founder of the resort on the Omatsuri Island, a recreational island in the middle of the Grand Line which the Straw Hats come to. However, he always challenges pirates who come to his island to a test called 'The Trials Of Hell' before he lets them relax, in which they must take part in a variety of competitions, ostensibly to prove their strength.

Source: Onepiece.wikia.com